On 08-09-19, 10:47, Peter Ujfalusi wrote: > > > On 06/09/2019 17.18, Peter Ujfalusi wrote: > > On systems where multiple DMA controllers available, none Slave (for example > > memcpy operation) users can not be described in DT as there is no device > > involved from the DMA controller's point of view, DMA binding is not usable. > > However in these systems still a peripheral might need to be serviced by or > > it is better to serviced by specific DMA controller. > > When a memcpy is used to/from a memory mapped region for example a DMA in the > > same domain can perform better. > > For generic software modules doing mem 2 mem operations it also matter that > > they will get a channel from a controller which is faster in DDR to DDR mode > > rather then from the first controller happen to be loaded. > > > > This property is inherited, so it may be specified in a device node or in any > > of its parent nodes. > > > > Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx> > > --- > > .../devicetree/bindings/dma/dma-domain.yaml | 59 +++++++++++++++++++ > > 1 file changed, 59 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/dma/dma-domain.yaml > > > > diff --git a/Documentation/devicetree/bindings/dma/dma-domain.yaml b/Documentation/devicetree/bindings/dma/dma-domain.yaml > > new file mode 100644 > > index 000000000000..c2f182f30081 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/dma/dma-domain.yaml > > @@ -0,0 +1,59 @@ > > +# SPDX-License-Identifier: GPL-2.0 > > +%YAML 1.2 > > +--- > > +$id: http://devicetree.org/schemas/dma/dma-controller.yaml# > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > + > > +title: DMA Domain Controller Definition > > + > > +maintainers: > > + - Vinod Koul <vkoul@xxxxxxxxxx> > > + > > +allOf: > > + - $ref: "dma-controller.yaml#" > > + > > +description: > > + On systems where multiple DMA controllers available, none Slave (for example > > + memcpy operation) users can not be described in DT as there is no device > > + involved from the DMA controller's point of view, DMA binding is not usable. > > + However in these systems still a peripheral might need to be serviced by or > > + it is better to serviced by specific DMA controller. > > + When a memcpy is used to/from a memory mapped region for example a DMA in the > > + same domain can perform better. > > + For generic software modules doing mem 2 mem operations it also matter that > > + they will get a channel from a controller which is faster in DDR to DDR mode > > + rather then from the first controller happen to be loaded. > > + > > + This property is inherited, so it may be specified in a device node or in any > > + of its parent nodes. > > + > > +properties: > > + $dma-domain-controller: > > or domain-dma-controller? I feel dma-domain-controller sounds fine as we are defining domains for dmaengine. Another thought which comes here is that why not extend this to slave as well and define dma-domain-controller for them as use that for filtering, that is what we really need along with slave id in case a specific channel is to be used by a peripheral Thoughts..? -- ~Vinod
